Comment by Elfie83

Comment by shadowspa

Their Cauterize ability heals them for 25% of their health (around 6,5 million), but leaves a DoT that deals 30% of their health over 30 seconds, essentially nullifying the effect. However, it will still take 25 seconds for the DoT to overtake the amount healed for, which can draw out the fight if you miss the interrupt (or in case your are a Shadow Priest or Balance Druid, are unable to interrupt a cast due to the cooldown on your interrupt). This is rather risky given that the High Priests have a tendency to kill you at the slightest slip-up.

The Ash, however, almost completely nullifies the healing effect of Cauterize, while still keeping the DoT, which overtakes the amount healed within 3 seconds and then continues to do about 7 million damage over its duration.

Since the ash only has a 10 second duration and has a slight travel time, it is important to anticipate Cauterize being cast so that you can apply the ash beforehand. The priests will start casting Cauterize once they hit 50% health, and will try to recast it every 30 seconds afterwards. This can easily be monitored in case they get their cast off (preferably while afflicted by the Ash), as the remaining cooldown equals the remaining duration on the DoT that Cauterize leaves behind.